Unpaid leave

Hi all,
Apologies if this has been posted before - I didn't find anything when I searched the Q&A section.
I start my first job in Belgium in September. My new employer advises that because I will have worked 3 months in 2011 I will be entitled to 5 days annual leave in 2012. I asked about unpaid leave and they're being a bit fuzzy about it, so my question is this. Are workers entitled to a certain amount of unpaid leave in the year?
Thanks.